One of the first game that really moved me and made me think about many subjects, including videogames themselves.
Takes a bit of time to really get into it, but I really enjoyed how the creators/designers tried to vary the experience despite the (I presume) kinda low budget; playing with camera angles, shmup sequences, the routes system with new characters and new mechanics, etc ...
The whole final act inside the tower is one of my favorite videogame finale / moment overall. I've replayed the game 4 or 5 times, and everytime I understand more stuff/ gain new interpretation on things.