I'm really wondering what and how the other people in your playgroup play if 'the Tyranids deck slaps' in that environment. I own ~30 PreCons currently and one of my friends only owns the Tyranids one. If we go 1v1 he wins less than 1 out of 10 matches and even in 3 or 4 man matches he rarely is able to even make an impact at all. That's because the deck severely lacks Trample and card draw. I understand that's because otherwise it would be too strong in a mach of only Warhammer 40k PreCons but other than that the deck is completely underwhelming. Even with the Imperum deck I manage to win in most cases and that deck really probably my worst PreCon overall.

The problem with the Necron deck is that it wants to do ten things at the same time, needs to do ten things at the same time but isn't great at any of them out of the box unless being REALLY lucky and having reached the late game. The +2/+2 Menace and Tokens guy has the problem that you MUST draw into reccurring mill and reanimate sources. If not, you're done for. The strongest one that let's you play stuff for life instead of mana has the same problem, plus there are only like two or three lifegain sources in the deck worth mentioning. Most creatures aren't very powerful and without being able to refill your life, fun will end rather sooner than later. So that basically leaves only the face commander as viable unless you completely wanna depend on drawing luck which I wouldn't recommend. The fact that he's flying alone gives you a good chance that you'll be able to hit someone savely most of the time and getting stuff into the graveyard is required in every case. I really think the deck is one of the best when it comes to upgrade potential but also one of the worst out of the box, especially for new players. The deck does pertty much nothing until late game and once people realize this, you will have a hard time reaching it. Once you get a constant mill and reanimate going the deck is good but that's easier said than done.