Fun idea, but kind of maddening that I can click and hold to add mass to a hole but if i overshoot, i can't do anything subtract mass or delete a hole.

This is somehow surprisingly fun, a good game to play with kids.

Fantastic! Should add an (optional) instruction level, but would have loved this game as a kid.

This is the year of old browser (and/or flash) games making a comeback in some form.

This is kind of a cool concept. It's like Space Golfing.

Another alternative is to make it like a turn-based Scorched Earth (Mother of all games), where you can either

1. launch asteroid size projectiles across star systems in a field of stars and black holes to it each other.

2. launch projectiles that then place black holes (perhaps either by timeout or signal--taking into account the speed of light!) to change the field.

It's a good start!

Very nice, being busy with sth, and I could not go through all levels and reached the one with star(sun?), but the topic of gravity assist manouver was always inspiring for me, so I enjoy this game, congrats on making it!

wow wonderful game this is super fun! Would love it on iOS

Never ignored a tutorial faster.

(This is a compliment.)