Honestly it already feels like there's a limit in that you need to roll ones with all of your dice currently available to get another one, and even if you just leave the last guy, you still are on a time limit for killing it before it does too much damage to the crystal and kills you.
Viewing post in Dicey Towers jam comments
It's definitely an advisable strategy to focus on getting more dice early instead of rushing to clear the first couple waves, but I think I might have made wave 1 too slow. Of course it does take longer to get each additional die though as you need to roll ones with all your dice, and the waves do ramp up in speed and volume. However, I agree it does need some balancing to prevent the player from getting too many dice too soon. I think simply tweaking the enemy movement speed in the early waves to put more pressure on the player would alleviate this concern. Thanks for the feedback! :)
A thought on that; instead of making the wave faster overall, why not a mechanic where the longer an enemy has been alive, the faster they get? An acceleration value, in other words. You can make it higher for the higher-tier enemies (so the reds would have a higher value than the blues, for example). That would make it still a safe wave early, but if you faff about too much without addressing the enemy, they can quickly overwhelm you, too.