I just finished the game - 5 stars in every mission. I used the Escape key as a pause key quite often. You can’t do anything while the menus are up, not even scroll the map, but you can at least see what’s going on, think about the current threat, and plan out layouts.
If you’re going to think of this as a tower defense game, it’s really a quantum leap beyond most of them. Including my favorite Defense Grid.
In most tower defense games, enemies are essentially big blobs of hit points, Fast, slow, armored or fragile, they’re fairly generic. Mostly they effect what weapons are optimal against a particular set of stats, but it’s often the case that you spam a particular tower type because all towers will eventually target all enemies, and the one that is most broadly effective works best. With Defense Grid for example you can beat most maps with gun tower spam.
Asteroids and the smaller ships retain that flavor in Space Run, but knowing the bigger ships matters. Putting up anti-missile defenses is important against ships with rockets or better. If the enemy has ion cannons, you must be fully shielded, because the disabling effect on unshielded components is absolutely devastating. If the ship has anti-missile defenses of its own, you need serious laser firepower.
It’s unfortunate that the built-in enemy database is vague about enemy ship designs. The color coded diagrams don’t tell you what you need to know. You need to eyeball the ship thumbnails, and those are usually at an angle that makes it hard to make out details of the ship design. It can be worth it to pause the game just to examine a particular enemy design in detail as it comes in range, particularly the bosses.
Most tower defense are about layout, but not to this degree. Firing arcs, power requirements, and shield coverage all combine to make this game heavily about careful ship design. By mid-game you simply cannot afford to be sloppy about placement, since a one hex error makes a huge difference.
Since enemies don’t pass by everything, matching weapons and defenses in a segment to incoming threats matters. If you have fighters or small asteroids incoming, you must have lasers. If there are big ships coming without anti-missile defenses, you can use missiles instead. Your own anti-missile defenses need to face enemy missile threats.
Generally speaking, you can’t afford to shield your engines. If you’re careful about putting them under shield umbrellas, you probably can’t make enough total thrust to 5-star the mission. In the late game, the most efficient layout is generally a couple of fusion generators powering banks of level-2 thrusters, which takes so much space that even the radius-3 shields can’t cover them.
The only components I didn’t end up having much use for are the Space Folder (level-3 drive) and Defense Complex (advanced anti-missile / ion cannon combo).
The problem is that the Space Folder takes up 3 rear spots and only generates 350 thrust, and 3 level-2 thrusters generate 600. Plus bonuses if you have extra power, of course. The Space Folder’s Hyperspace special ability can shave time, but it’s also a huge headache because it can dump you right next to enemy ships. I found that just being fast with regular thrusters worked better.
The problem with the Defense Complex is simpler: it’s big, it’s an awkward shape, and it needs an outer hex. Shoehorning it in is tough.
While all those special actions make the game look hectic, in practice you usually don’t want to activate any ability that costs nuts. It’s better to build something instead. The special abilities mostly come into play against bosses, since you usually have a big nut surplus by the time you face one.
The exception is Materialization on the level-3 power generator, since it’s a discount to building cost. If you have 300+ to spend at once, Materialization saves you money as well as time.
It’s better to think of the biggest weapons and bigger shields as requiring 1 more power than listed, because it’s so cost effective to gain the power bonuses once you’ve unlocked them. Going from 2 power to 3 is a minor increase in cost for a big increase in firepower for the level-3 laser and level-3 missile launcher. Similarly, an extra point of power makes the level-2 and 3 shields much more durable.