Look for Crystals!
Crystal Caves is not your regular mindless sidescroller platformer, where you can get away from any situation by shooting or jumping. Nope, this one, when it gives you a weapon it also gives you very limited ammo, so that you have to think well before using it. There are levels where a weapon is only good for one single use, and if you don't shoot what needs shooting you can lose the game, and you might need to start again. Yap, every level needs to be tackled as a puzzle challenge. In fact, every little nook of the sprawling caverns you'll be walking about requires you to solve some little puzzle or develop some kind of strategy in order to go past. In terms of graphics, it is a cartoony game, pretty good loking, Dossy like, and quite clean. In the series I'd say it's just as playable and as okay looking as the others that will follow as this series hadn't really evolved that much over the years. But, definitely, if you have love for 2d exploration and for little sidescroller puzzles, this one's the one to turn to.