I found this game super enjoyable. After I got the hang of it I found clearing each floor very satisfying and getting new skills very rewarding. I could definitely see myself putting a lot of time into this game, especially if audio were to be added. I think one thing to be wary of is making the player wait for skills to tick down, like maybe playing a skill could just subtract time from the timer? But here I never found myself getting too bored while waiting, so I think it works reasonably well.