There were a number of snipes that I had placed through BidSlammer within the past day, and specifically with the eBay seller "kidlongshot". In numerous cases the bids were not made (one item ended with zero bids). Others I lost even though I would have been the high bidder. What happened?

Hello Warren,
Thank you for your question about the numerous bids you placed with one seller. We reviewed what we encountered on each of your snipes.
Unfortunately, there are some circumstances we can't catch until we place the bid. Sellers can set preferences, but many of them are are private and not disclosed to us. Our best resource is the "Bulletproofing your snipes" page, with two other links containing a comprehensive list of reasons:
https://bidslammer.com/help/bulletproof/
TL;DR: For you, we can rule out: No PayPal account or unlinked account; unpaid items; buyer strikes; invalid ship location; using a PO Box; policy breaches; and low feedback. The one that seems to apply here: Currently winning or bought 1-100 items from that seller in last 10 days.
If this is a recurring issue, please let us know so that we can try to account for the issue in our software. We welcome any follow-up comments or further suggestions you may have.