Super Turrican 1 is easily the best Turrican game. It's a fantastic run & run platformer, with great graphics and music, highly-polished gameplay, and lots of great stuff to see (and shoot) along the way. Mega Turrican is my second favorite Turrican game, and it is close to Super Turrican's level, but Super Turrican is slightly better, I think. Both are incredible, must-have games, though, among the best games on the SNES and Genesis, respectively.
When comparing Manfred Trenz's two games, the first two, to the three later ones Factor 5 made themselves, there are a lot of differences, as F5 made their games with a much stronger arcade/Japanese influence than you see from the first two. The first two are clearly Euro-platformer(/shooter)s, but that changes with the third game. People, mostly Europeans, who grew up with that style of game naturally then dislike the later titles for being different, but as an American who grew up on mostly American and Japanese games (NES, PC, etc.), I think that the direction Factor 5 went in improved the series. I'm not a "Euro-platformer" fan, of the games of that style from the '80s to early '90s, admittedly, but still, as great as Turrican 2 is, the later ones are even better. Turrican is a really great series, one of the best run & gun game series ever -- for me only Metal Slug is definitely better (never loved Contra...). I love Factor 5's later games as well, too -- the Rogue Squadron/Battle for Naboo games are outstanding! Great developer...
For the first two games, they're interesting mixes of European platform-action style, with some Japanese influences. I love the Metroid-inspired ball form, and the shooting action is good, but they have issues. Now, Turrican 2 / Universal Soldier is a great game. I like it a lot, and the Genesis version is seriously under-appreciated -- it's actually quite a good port, and I really like the addition of password save, more Turrican games should have had it. It's improved hugely over the first game, too, as Turrican 1 is way too hard (the original game is EASILY the hardest Turrican game of them all, by a lot!), has more than a few blind jumps over death pits in an annoying way that Turrican 2 and beyond avoid (this is a HUGE improvement in the second game!), made it so you now can bounce off of some enemies without taking damage (in the first game all enemies hurt you on touch), level designs have been improved all-around and are more fun and not quite as crushingly difficult as before, and more. But both games have things such as no invincibility on hit, aimless levels which can sometimes be fun to explore but other times can be a bit annoying when you spend time exploring somewhere only to lose more health than you get back and get little but some not-too-useful points, levels that due to their size and open designs can't have as many of the type of action set-pieces that make run & gun games exciting as would be nice. and such. And while I like collecting, I also like having direction. Still, in Turrican 1 you can see where what made the series great came from. Unfortunately it's too flawed to be great, but it's not awful either. The computer versions are better than the console ports, though the Genesis version isn't too bad (and is the only console version with all the levels in it); the game has issues in any format. I don't dislike Turrican 1 as much as some people -- you'll see people, particularly those who only know it as a console (mostly Genesis) series VERY harshly criticizing Turrican, calling it terrible, etc -- but it is quite flawed.
With Super and Mega Turricans, Factor 5 put in a better health system that doesn't drain while you touch enemies but instead has a more normal hit-flash-and-momentary-invinciblity setup; much more focused levels that still have some of the exploration of the first two but now with smaller overall sizes; and better level designs that are much more focused. They are still somewhat open at times, but not as much so as the previous games and I am quite fine with this. I have always preferred a more directed experience over an open-world one, and Super and Mega Turrican get the balance between exploration and focused set-piece action exactly right. They are easier than either previous game, to the point where while both have limited continues (as all Turrican games except for Universal Soldier have), it shouldn't be too hard to finish them. There is enough challenge to keep me interested, though, and they are incredibly fun regardless of challenge. The levels, bosses, and obstacles are all interesting and fun to deal with... just awesome games. I like Super more than Mega for several reasons, including the slightly better graphics and music, but also the mechanics --- Super has a freeze-beam as the beam weapon, replacing the beam gun from 1 or 2 you got when you held the button down, while Mega has a slightly awkward grappling whip thing that can be hard to use well. I like the freeze beam more. Both games are in my top 10s for their respective consoles, though!
As for Super Turrican 2, the last game, it's very different from the past ones -- the game is almost entirely linear, with next to none of the larger stages that all the other games have. It's a really good run & gun, but it definitely has a different feel to it even versus Super and Mega Turricans because there are many more set-pieces, and almost no exploration. It's a great game of course, with fantastic graphics and lots of fun, well-thought-through high-intensity action, though. And it's tougher, too. This is probably the hardest Turrican game since the original. It's also got both a freeze beam and a grappling hook, and I like that the grappling hook is easy to use this time -- it just goes out at a set angle when you hit the button, instead of the more controllable, but harder to use, Mega Turrican version. But still, as great a game as Super Turrican 2 is, I do like Super and Mega Turricans slightly more. Turrican 2 is probably also better, but it's close. (Turrican 1, of course, is far behind all of the other four; it's only maybe average, forget great like all four others are.)
