Can't say that it is particularly hard to get two successes, especially if you are using 1-2 ROF and is pushing your skill roll. The pushing mechanics is a core mechanics in YZE-games, not only does it increase your chance to hit a lot it also increases your chance of getting more than one success.
YZE-games can be very deadly, this is most likely the most deadly of them all (well, Alien RPG).
We've only had one larger firefight so far in our test-run and one of my lead player's almost lost his character and is now expecting to loose him during the next session. The party was lit up by enemy automatic weapons in fire teams and on one BMP-1 and a ASU-85. Previously the enemy AFVs had destroyed the player's (NPC driven) only AFV, a German spotter tank (thinly armored as it was).
Background: The players are pre-Kalisz on a relief and support mission for the 5ID. Basically, they're German Bundeswehr (plus a Polish liason and a US SF scout) and are supposed to guide artillery support for 5ID retaking Kalisz before SHTF there.
They've stopped at a Polish territorial army academy, which is now run by kids as a center of operations for their resistance movement (cf. 'The Children's Crusade' from the box set). They needed to evacuate the academy due to a superior force of Polish communist militia imminently attacking the academy. The players just managed to scramble off with the last children in softskins, when the enemy arrived with AFVs and three squads in trucks. As enemy forces approached, they began laying down fire on the trucks and other vehicles the players rode in.
One player 4x4 was hit and damaged in the tires, but the players themselves suffered no casualties. It came close to that several times, though, when players started failing drive rolls and even fumbling then after pushing, nearly mauling some of the kids, when the player's 4x4 drove into the kid's civilian car and its ad hoc built trailer.
Bottom line is: Base damage might seem low at 1 for pistols, 2 for 5.56 rifles and 3 for 7.62 rifles or machine-guns. However, since the crit value is usually just one point higher than base damage, one additional success, or two if the target wears regular armor, will give you a crit. With 2D8 and 2D6 for short burst fire, that's easy to accomplish.
Additionally, you can always use additional successes to inflict additional hits, even on multiple opponents, if the additional successes come from ammo dice. This will also inflict CUF rolls on the enemy, which in turn might suppress them. But even then, a regular fireteam with 3 soldiers carrying assault rifles and 1 carrying a machine-gun will generate around 8D8 and 12D6 (assuming an average 3D6 per gun fired) in a firefight, but might actually generate 24D6, if armed appropriately and using all weapons to full potential. Yes, this will use up 80-100 rounds per round on average, but that's mute point, if salvage afterwards reaps a harvest of guns and ammo the enemy never got to use.