cool as a first entry!
In my opinion, games feel more engaging when there are a multiple game mechanics that interact with each other. It's a bit more challenging with this jam, since the theme was One Ability. For example, VPNs could bounce off the wall, cloning themselves in the process, unless they hit hacks before. So as a player, there would be an option for me to shoot directly at the hacks (which is currently your only option), OR you could shoot at a wall, to have more VPNs on the board later.
But, you don't want to have too much stuff going on. I think the right balance is when there is enough complexity for the player to be able to make a meaningful choice between multiple approaches, but it's simple enough that it's the choices are obvious and can be easily kept track of.
Edit: Also, it's not universal. Some games are more about skill, they just challenge the player with a task, that the player needs to do fast/precisely, without much choice at all. If the task itself is fun to do, that that can also be a good game, with little complexity.