1. Is the SEGA 32x region-free? I only ask because to play Kolibri I may have to import a US 32x as the PAL version of Kolibri seems even harder to come by than the already rare NTSC version.
Sort of. You'll need to mod the 32X with a 50Hz switch, if you want to use it with a PAL Megadrive. This thread should help:
http://www.sega-16.com/forum/showthread.php?t=4174
32Xes should plug in to Genesises from any region, though... I think... but US/Japanese systems are 60hz and European ones 50hz.
2. Will it matter if i'm using a NTSC 32x with a PAL Megadrive (fitted with region-switch & 50/60hz switch)?
Initially, the only difference between Genesis games from different regions was cartridge shape and PAL/NTSC. However, midlife Sega added region-checking, so many later titles would only run in a certain region system.
There are three modes: PAL Megadrive, NTSC Megadrive, NTSC Genesis. Europe, Japan, and the US, that is.
Just like with the Genesis, 32X games vary. Games are either region-locked or not; region locking can lock out two regions or only one. Some games have region locking in some releases, but no lock in others -- for instance Alien Soldier for Genesis, for which the European release is PAL Megadrive locked only, while the Japanese release is not locked (but is 60hz only so it will run too fast on a PAL TV). In this regard, the 32X works exactly the same as the Genesis. Some games have locks, others don't. Some are single region, others multi-region.
Really, the best way to know which are which is emulation (legal issues aside)... Kega lets you select the region of the system, so you can see what will happen when you load a US 32X game into a European system, for instance. There are also several FAQs with lists of Genesis/Megadrive games that have region locks, but I don't know of any for the 32X...
Of course, part of this is because most games came out in both the US and Europe. There are only a very few games that only came out in one region:
There were 34 Sega 32X carts released worldwide. In addition, there were five CD32X games released, all upgraded versions of FMV Sega CD games, and all, I believe, US only. Sega-16 and Wikipedia list European releases of the five games, but I see no proof that they exist... I doubt it.
Of course, given how a simple little application can change the region of a Sega CD ISO and the Sega CD plays CD-Rs, all that would need to be done to play a US 32XCD game in an unmodded European Sega CD would be to make an iso of the cd in question, change the region of the iso, and burn it.
Complete list, with regions listed for each game:
http://en.wikipedia.org/wiki/List_of_Sega_32X_games
1 game is Japan-exclusive, 2 Europe-exclusive (including the VERY rare, PAL Megadrive only region-locked, and graphically impressive Darxide), and 11 carts and all 5 CD32X titles US exclusive.
3. Beyond the games i've already marked down as 'to buy' (Kolibri, Knuckles Chaotix, Star Wars: Arcade) are there any other 32x exclusive games worth owning?
4. I hear the 32x version of Blackthorne has extra levels over the Megadrive/Genesis version - are there any other 32x versions of Megadrive/Genesis games worth picking up? (i.e - WWF: Wrestlemania Arcade, Mortal Kombat II, Pitfall, Afterburner etc)
The complete library is so small that, if you have one, it would kind of make sense to just get most of them...
Either way, there are definitely more games worth looking in to, beyond Kolibri, Knuckles Chaotix, and Star Wars Arcade.
Darxide -- if you can find it somewhere (hah, good luck)... you have a PAL system, so it'll work. It's basically 3d Asteroids, with the best graphics of any released game on the system. Texture-mapped polygons!
Shadow Squadron -- one of the system's best games! Great 3d space combat sim. Better than Star Wars Arcade. Don't even think about playing this without a 6-button controller. Not long, but really good while it lasts...
After Burner -- great port of the original arcade game... FAR better than After Burner on Genesis or before (though the Sega CD one can compete, since that hardware also had sprite scaling).
Space Harrier -- great port of the original arcade game. Blows away every previous Space Harrier game release! After Burner and Space Harrier should be 32X must-buys.
NBA Jam T.E. -- Widely considered to be one of the best, if not the best, home version of the arcade great. Have a multitap...
Tempo -- Solid, fun side-scrolling platformer. Had a Japan-only sequel on the Saturn, but the first one had a Western release.
T-Mek -- 3d tank action game. Kind of like the original Battlezone, really. Very simple game.
Metal Head -- another tank shooter, but this one's a bit more complex. Quite nice graphics (it has texture-mapped polygons! Very rare, for this system...), for the system... it has mixed reviews, but I think it's fun. Have a 6-button controller!
Zaxxon's Motherbase 2000 -- Really more Viewpoint than Zaxxon. Often considered disappointing, but shmup fans will want to check it out anyway. The way you can take enemy ships over is interesting and different.
Blackthorne -- Indeed, maybe the best version. Different graphics from (ie better graphics than) any other version, and the same great gameplay.
Virtua Fighter -- Great port of the first Virtua Fighter game! It's a better port than the original Saturn release.
Virtua Racing Deluxe -- fantastic racing game with pretty nice graphics brought down only by the fact that it has no saving to back up your lap times... get it anyway.
Probably don't bother with: Motocross Championsip (just awful...), Cosmic Carnage (terrible fighting game), Doom (Better graphics than on SNES, but it's missing the last third of the game! You finish chapter two and... that's it. Huh? Plus, the SNES version has more levels, FAR better music, and level designs that are more accurate to the original PC maps.)