Owner of the game here.
The Alien Event cards and some action cards used by the space marines remind me of the Combat Cards and Evil Wizard cards.
We said we miss that mechanic in HQ so we implemented it. And then we got creative.

Space Crusade has a number of problems. But there was an upside: It was the source for the mercenary system in HQ, later. Because that part was good, apparently.
Problems are:
1. The game doesn't really scale with the players.
Yes I know you are supposed to use more blips if there are more marine players, but no, it doesn't scale. A single marine player dies by just using the event deck. Two marine players play more or less balanced. Three marine players just flatten the Chaos player with very few losses, if any. Worse, the Event Card Deck is really bad for a single player because he takes longer to achieve the mission, and less bad for three players because they fulfill the mission in 5-6 rounds; so that's inverse balancing. So I proposed some solutions, including event cards that scale per Marine Player. Like "Place one Genestealer next to each commander" instead of "place one Genestealer"; or taking more event cards if there are more players.
2. Either the monster points or the marine points are not in the right range, but at least to me it seems as if the Marines can make much more points than the Chaos Player.
3. They lost the creativity for Mission design somewhere in the middle. I think there are two or three creative missions, all the rest is just "Go kill everyone". Well, that works better with a skirmish game like Necromunda or 40k Kill Teams, doesn't it? What was appealing to me was the fact that marines go aboard to fulfill a mission that couldn't be achieved otherwise. Kill everyone, you can play battlefleet gothic and stack some broadside markers on the shields, done. But then there was the PC game (or was it the Amiga Game?) where there were really a couple of interesting missions. I liked that one! Same for 40k:Chaos Gate which was a 90ies isometric round based computer game with the same gameplay feeling. You could cheat that game without end if you wanted, but it was fun. It was exactly that mix of RPG and tactical wargame that any heroquester would love. One game with 5 marines would take hours, but that's a price you like to pay for the fun, right?
4. Once I started to add more Orc variants to the game, I suddenly had a 40k Army. Ok, that's a personal problem of mine.
The red dice have 0,0,0,1,2,3 yes. The white ones have 0,0,0,0,1,2. I've made myself blue dice with 0,0,0,1,1,2. They sit exactly between the red and the white dice and so give a game designer the ability to invent weapon variants without end; which I used, no surprise, to add all the 40k stuff of my cupboard to the game. That includes a small imperial army, an awful lot of Orcs, a few more Chaos Marines, one unit of Necrons, some genestealers. Then I played it with myself for testing. When I was satisfied, I brought it to the 40k club, and they didn't want to try it at all. That was bad.
So I stopped again. Instead I played my Orc Army for some years, successfully.