the title says it all
Ideas for game/suggestions
- dig dug game but the mine suffers from flooding.
- Cranked, You must kill a enemy every 10 seconds to live.
- big fish little fish in space: ram other ships to destroy and get parts. then craft to become bigger.
- quick draw game with gun jams. Now players must fight to death like nidhogg.
- randomly generated zelda style dungeon. One room one exit. rouge kike.
If you really want to exercise creativity then maybe you could try watching more films, reading books, or even playing other games. You'd be surprised how many movies and books have ideas that could easily be implemented into really cool game mechanics that almost no one else is doing. If all else fails, sometimes even just playing a genre of game you like, horror, fps, strategy, and making one of your own with your own twist can be enough. Look at Crossy Road and Candy Crush. Just don't be lazy by going full Clony Bird level of development.