I know that everyone is excited about killzone, but i'm posting impressions on superfrog hd:
-Characters are very well animated, the graphics of the first world is awesome, while the one of the second world is just good, anyway the game is way better than the screens released long time ago.
-there are 48 levels, 24 new(inspired to the original but different) and 24 original levels, the original levels are the levels of the original amiga game, they are big, have the awesome original musics and you need to get a certain amount of money to open the exit, the new ones instead are HUGE, have new musics and you simply need to find the exit(but if you want to get the 3 stars score you need to get as many money and fruits as you can).
All levels are filled with (huge)secret passages and are non-linear.
-the green ball attack changed a lot, it was originally an "anti-air" enemies attack, the default attack was front-up and it was futile against ground enemies(if i remember correctly), now it's effective against all the enemies and the default attack is in front of you, making the game a little easier imo.
-there's an endless runner mode with limited time and time bonus, sadly the "portions" of levels are big and repeated, but it's good anyway.
-there's even a level editor!
-the original amiga opening was animated, while the one in the hd version is not lol!
-i would have preferred the original sound effects, but that's a matter of preferences i guess.
I'm still early in the game but i can already say that is a good remake(unlike alien breed) and an awesome platformer(especially in the original levels)