Two grounds to the neutral bus bar of the main panel. One disapears into the foundation wall, presumably to a ground plate or rod, the other to the gas line. I am thinking they are using the neutral because the gage is too thick to easily fit in the smaller ground screws of the panel. There is a copper water line, but they did not use it. Pex water line distribution to all the fixtures. I can’t think of a reason why this would be wrong, but I am not an electrician.
Thanks in advance.
Gas line connection is a bond.
OK, so is that a good thing 
Unless the gas pipe is CSST a separate bond is not required. If there is a metal water pipe system it requires bonding but you do not have a complete system so that is not required either. Seems odd that they separated the neutral and EGC’s on separate buses within the panel. Also there should be a bolt or retention clip on the main CB. Do you have any other photo’s as they may indicate other issues.
Regarding the “grounds on neutral” question…
This is perfectly acceptable (in the States) as long as this is the main panel (which you said it is) where the neutral to ground bond exists (which it looks like on the upper left side of the picture a bonding strap attaches the neutral bus to the can)
So regarding that issue it seems to be ok.
As Robert said, main breaker retainer should be present and the work doesn’t seem very organized so a larger picture might indicate other issues.
To me this looks like a combination panel…service panel on top and distribution panel on bottom. In the first pic the service panel cover is removed and in the second pic, the service panel cover is in place.
Grounds and neutrals are not allowed to come together in the distribution panel. It’s not real clear, but it looks like they do.
The just looks like a panel with the breakers serving as the service disconnect, not a combination panel.