Great game, I had the same resolution problem but it worked out when zooming in to 150% like someone else said. I started the game at level 2 and realised quickly that this would be hard haha. But it was really fun and when I got a hang of the game and the different possible upgrades I challenged level 4. After a couple of tries I won! Level 5 was too hard for me though. I think I played too long so the sound stopped working haha but I restarted it and got it back. Simple idea but I am not sure what you could add except some different upgrades I guess.
I thought that U and V was too similar in the font so I destroyed those letters usually :)